The general progress and present status toward commercialization of salmon and trout transgenic
fish for an "all fish" chimeric growth hormone gene construct are reviewed. We anticipate no risks to
human health as the entire gene construct is derived from edible species of fish; however, there remain a
number of environmental concerns that need to be addressed before the technology can be applied by the
aquaculture industry. Under pending Canadian regulations for the use of transgenic fish in enclosed
research facilities or hatcheries, a case is made that compliance with proposed containment measures as
shown in the design of the facility should result in little or no environmental risks to natural salmonid
populations. Attempts are then made to assess the effectiveness of current fish containment and
sterilization techniques in order to reveal factors of risk involved in commercially culturing these fish in
land-based systems and in ocean pens. Many of the risk issues confronting the application of transgenic
technologies are not particulary new and have been encountered in the past by fisheries managers and
aquaculturists in relation to salmonid transfers, introductions and selective breeding. Some contrived
examples of impacts (real and perceived) are developed for non-endemic species such as steelhead trout
cultured in Newfoundland. Factors considered include probabilities of escape, adult survival, migratory
behaviour, spawning success, sex ratios, reproductive sterility (triploidy effectiveness) and offspring
survival, inter- and intra specific competition and gene fitness. It is concluded that the magnitude of risk
will depend on the nature of the gene construct and its phenotypic effect, and will vary between different
salmonid species and ecological regions. Present sterility techniques will probably be adequate for some
species in most circumstances, but may not sufficiently reduce risks (or be commercially viable) for other
species under other conditions. Considering the lack of present understanding of the fitness (behavioural,
physiological and genetic) of such transgenic fish, it may be exceedingly difficult to predict impacts in
many situations. If sterile transgenic fish were to be used in aquaculture, risk to native salmonid
populations would likely be no greater (and probably less) than under present operating conditions in which
non sterile fish are being used world wide.

Workers at Memorial University began injecting salmon eggs in 1983 with an antifreeze protein
gene construct derived from winter flounder in an attempt to provide protection from ice formation in the
tissues of salmon being cultured in cold climates particularly in Eastern Canada. Although the gene has
been incorporated in subsequent generations in a heritable fashion, the quantities of the protein produced in
salmon to date have not been insufficient to provide a safe margin of thermal protection (Fletcher et al.,
1988). In 1988 injections were initiated in Atlantic salmon using a transgene consisting of a fish (eel pout)
antifreeze protein gene promoter fused to the growth hormone cDNA from chinook salmon. Gene
injections through the micropyle of fertilized, but non-water-activated salmon eggs, have routinely led to
about 2 to 3% incorporation of the gene in developing juveniles. These fish consisit of a mixture of
somatic and germ line mosaics (Fletcher and Davis, 1991). Of these gene carriers, about 25% of the fish
actually pass the gene (and the rapid growth characteristic) to a of the F1 generation, resulting in anywhere
from 1 to 20% transgenic progeny (Hew et al., 1995). A stable inheritance pattern at the F2 generation has
been demonstrated and explained by from 1 to 4 chromosome inserts, with transgenic fish growing up to
ten times times faster than their non-transgenic siblings. Male heterozygous brood fish presently on hand
are capable of producing 50% fast growing transgenic salmon when mated to wild female salmon and
indications to date suggest that size grading at a weight of less than 5 grams is an effective method of
separating transgenic fish. In some of the transgenic lines of fish, the transgene, although incorporated (as
detected by PCR), is not expressed in the form of enhanced growth. Problems exist in certain transgenic
lines with skeletal abnormalities and with higher than normal early mortalities rates. Techniques (reverse
PCR) are available to identify the exact number of chromosome inserts possessed by a fish and which fish
have homozygous inserts; work is planned to apply these methods to enhance the breeding program.
Preliminary results suggest that gross food conversion efficiency of transgenic salmon are likely to be as
good and or better than that of normal salmon. A/F Protein Canada has licenced the patented technology to
companies in Scotland and New Zealand and is actively working with these companies to assist them in
developing transgenic fish using their existing brood stock. Injections of the same construct into rainbow
trout eggs were initiated this Spring at our new research facility at Prince Edward Island, and we anticipate
that progress will be more rapid with this species as the triploid technology is perfected and readily
applicable for the production of reproductively sterile trout. Injections are also planned for Arctic char this
fall.

POTENTIAL NEGATIVE IMPACTS OF TRANSGENIC FISH

ON WILD POPULATIONS

Many of the concerns (Kapuscinski and Hollermann, 1990 and 1991) associated with the use of
transgenic fish in fish culture are not particularly new and have been encountered in the past in one form or
another by the aquaculture industry and fisheries managers (see NASCO CN(93)29, 1993). These relate to
the use and possible impact of the escape of exotic (non-endemic) or highly selected species, strains or
stocks, fish hybrids and fish with manipulated chromosome sets. If the new or genetically modified fish is
reproductively sterile, the fear of genetic introgression, genetic drift or swamping of native gene pools is
lessened (Devlin and Donaldson, 1992). Even then, however, a considerable degree of apprehension among
fisheries managers and the public is likely to remain even with sterile transgenic fish and must be
addressed.

As discussed later, unless the aquaculture operation is entirely land-based with rigid containment
methods in place, there is always the possibility of sterile transgenic fish escaping into the wild. This is
particularly the case for culture operations using lake or ocean cages where the appearance of aquaculture
fish returning to local rivers has been well documented (Ludwig, 1996; Gausen and Moen, 1991; Skaala et
al., 1991). Present production of Atlantic salmon is almost inclusively conducted in sea pens and unless
the performance of transgenic salmon becomes truly remarkable, it is doubtful that a sizeable portion of the
industry would switch to more contained land-based, pumped systems in light the high capital and
operating costs of the later. However, sufficient containment of transgenic trout in land-based farms using
tanks or raceways would appear to be possible Even in situations where industry has for environmental
reasons adopted the use of non-transgenic, all-female, triploid fish (99% sterile), there is still concern over
the direct effect of escaped, long-living, free-ranging predators on natural fish populations as well as their
potentially competitive interactions for resources such as food and space (Sutterlin and Collier, 1991).
However, the use of sterile transgenic fish does allow for a period of assessment with the possibility of
reversing negative consequences through discontinuing use of the novel genotype (Hallermann and
Kapuscinski, 1992). Although it is the expressed intension of A/F Protein to maintain all experimental
non-sterile transgenic broodfish and juveniles in secure confinement while refining techniques for reliably
inducing sterility prior to any application for field trials, the two most disconcerting questions that remain
(and are discussed later) are:

What is likely to be an accepted level of sterility for transgenic salmonids for use in commercial land-based
and cage rearing operations?

How can the issue of direct competition of sterile transgenic fish on the ecology of natural systems be
addressed?

CONTAINMENT OF TRANSGENIC FISH FOR RESEARCH PURPOSES

A/F Protein has recently purchased a salmon hatchery on, Prince Edward Island, specifically for
the purpose of conducting research and developing transgenic salmonid brood stock (Figure 1). The
following set of selection criteria set out in the initial search for a facility have been satisfied:

The plant should be based on a sizeable quantity of ground water of high water hardness.

The plant should have sufficient water and tank size and space to rear salmon and trout to maturity.

The facility should already be disease certified or be capable of FHPR Certification.

All rearing space should be confined within a secured building

All water should leave the plant through a common drain

Effluent water should not discharge into a major system containing salmonid fish

The building should be structurally sound and of sufficient elevation to preclude flooding

Security systems must include automatic telephone call out and remote paging

Living accommodations should be available in the building so as provide 24 hr security

The installation of a hall way to allow entry to the upper level office /living complex while preventing
access to the rearing area

The replacement of present door locks with heavy duty units

The installation (figure 2) of an in-ground concrete sump equipped with two sets of 1mm mesh screening to
filter all effluent and automatic methods to detect screen fouling

The recruitment of an antisocial, vocal canine with an attitude problem

The size of the screening has been set to retain the smallest life history stage of the organisms in
use. For salmonids this involves preventing the passage of first feeding fry with the lower size limit set for
that of Arctic char which are smaller than the fry of rainbow trout and much smaller than that of salmon.
At least three levels of screening are provided for each rearing unit. Incubators are equip. with 1 mm
screens that filter the water from each stack of incubators containing transgenic eggs. Water discharge
from the fry tanks pass through a rotating drum filter (200 micron screen) which is necessary to remove
sediments prior to heat effluent heat recovery using heat exchanger and heat pump. The back wash from
this screen enters a domestic septic tank and blind weeping field. All other effluent leaving the hatchery
must pass through a double (1 mm) screened concrete sump buried in the ground and accessible through a
locked steel hatch. Inexpensive aluminum window screening works fine but needs to be supported by 1/4
inch galvanized hardware cloth. It is important that the water be allowed to fall a distance of at least 12
inches before striking the screen or the screen will quickly foul. Test with submerged screens proved
unsatisfactory as then fouled in several hours.

Should the upper most screen become plugged and begin to overflow onto the lower screen, a float
switch activates a telephone monitoring system that begins calling hatchery personnel at their homes as well
as activating their pagers indicating a screen overflow code. The lower screen provides the filtration until
personnel can replace or clean the upper screen.

Presently in Canada, regulations concerning contained research, field trials and commercial
production of transgenic fish are evolving under the Federal Department of Fisheries and Oceans in the
form of a draft document entitled: Transgenic Aquatic Organisms: Policy and Guidelines for Research
with, or for Rearing in Natural Aquatic Ecosystems in Canada. The policy is presently in its 3rd or 4th
draft and is still under government and industry review. A/F Protein will likely be the first private
company in Canada to apply for a research permit under the new regulations and in consultation with DFO
in Ottawa has determined that voluntary compliance with the draft regulations could provide some valuable
practical experience for both government and our company prior to any required licencing or legislative
implementation of this policy. A/F Protein applied in early April , 1996 for the prototype research permit
and has been working with DFO officials locally and in Ottawa to install the mutually acceptable
containment measures described above. We anticipate a final inspection of the facility in August, 1996.

REPRODUCTIVE STERILITY OF TRANSGENIC FISH

Presently available and potential future methods of sex reversing and sterilizing salmonid fish have
been described and/or reviewed by Devlin and Donaldson ( 1992), Hunter and Donaldson (1983) and
Pepper (1991).

The most promising of presently available techniques include the following:

Direct oral androgen treatment of juvenile fish producing a high frequency of sterility in both sexes.
However there is some public concern (perhaps of questionable merit) over treating even juvenile food
fish with steroids.

Hormonally sex-reverting female fish to male fish and using the resulting milt containing only X
chromosomes to create an all-female population of transgenic fish. This approach would only be
acceptable in highly specific situations where wild males of the same species were not available to mate
with escaped transgenic females.

Inducing triploidy in the above all-female population by the use of heat or pressure shock shortly after
fertilization with the sperm bearing only X chromosomes. Triploidization of mixed-sex population of
eggs is not recommended as male triploid salmonids do sexually mature and could possibly contribute
to spawning activities resulting in lethal aneuploid offspring.

Although there are a number of alternate pathways to achieve the later objective, the final outcome
results in a population that is entirely female providing the sexual genotype of milt donor is properly
identified and providing the lots of fish or eggs do not become mixed up with diploid groups at the
transgenic production facility. Maintaining juvenile diploid brood stock or other diploid production lines
in separate rooms or buildings would be a recommended approach. In rainbow trout and Atlantic salmon,
identification of first generation sex-reversed females from normal males can quite easily be accomplished
by examination of the gross testis and sperm duct morphology, and a molecular sex probe, although
perhaps desirable, is not required. In any event, a simple gonad examination of a small sample of juvenile
progeny will confirm the mono sex status, and in subsequent sex-reversed brood stock generations this
problem becomes inconsequential.

There also are also a few uncertainties relating to the interactions of the triploid and transgenic
condition that might influence the final breeding methods (maternal or paternal transgene contribution) to
be adopted depending on the relative commercial suitability of heterozygous or homozygous transgenic fish.
Because there is a doubling of maternal chromosomes involve in the triploidization process, disruption in
transgene control is a possibility although this does not seem to be the case with other genes in triploid fish
(Benfey, 1997).

THE NUMBERS GAME

Quite apart from the concern over direct effects of escaped sterile transgenic fish described later,
the acceptable frequency of non sterile transgenics fish in a production lot destined for a commercial
hatchery and eventually to a sea pen grow-out operation, might logically also depend on the following
factors:

The past record (frequency and magnitude) and probability for future escapes of fish at these sites

The survival and reproductive effectiveness of the transgenic fish

The presence, size and importance (environmentally, commercial and recreational) of local native
salmonids of the same or hybridizable species

The nature, stability and resulting phenotypic fitness due to the transgene in the initial and subsequent
generations

In an attempt to avert any genetic consequences, perhaps one of the more uncertain obstacles for
the producer of transgenic fish will relate to the efficacy of the triploid induction process which will
determine the frequency of non-sterile fish in the production lot and as such could become an
environmental control issue. The effectiveness of heat and pressure treatments, summarized in Table 1,
suggest that with experienced operators it should be possible to produce at least 99% sterile fish even if the
treatment results in a financially tolerable 20% loss of eggs. There also appears to be a consensus
developing by scientists and industry that pressure is a more reliable method than temperature for triploid
induction. The cost of a 4-liter pressure vessel ($C 20,000) and time required to treat salmon eggs at a
20,000 eggs per batch (30 minutes) does not appear to be commercially insurmountable.

For example, it may be feasible to examine the blood cells (Coulter sizing or determining their
DNA content by flow cytometry) from 100 or possibly even 1000 fry resulting from each pressure treated
group of eggs which would detect the presence of a single diploid fish in a sample of X number of fish at
the Y percent confidence level when they are present in the population at the Z % incidence. Batches with
unacceptable levels of diploid fry could then be excluded from further commercial production. Table 2
(from Ossiander and Wedemeyer, 1973 ) shows the sampling effort required to detect a single diploid fish
at the 95% confidence level when their frequency in the population varies between 0.5 and 10%. However,
it should be noted in Table 1 that the size of the sample in these studies are all under 100 fish and this low
level of screening would (from Table 2) not likely be adequate to detect a low diploid incidence in large
populations. Therefore, the question remains: what level of triploidy will be deemed environmentally
acceptable and can sufficiently sensitive and affordable screening methods be devised to meet these
requirements?

It becomes apparent from Table 2 that treatment lots based on eggs from each female (5,000-10,000 eggs) will not be a cost efficient method of screening if blood samples from the required number of
individual fry must be examined. Flow cytometry, however, is sufficiently sensitive to enable pooled
blood samples from fry derived each treated female to be used. Screening treated fry from pooled samples
of treated eggs from several females may have some disadvantages in that variations in triploidy
effectiveness, possibly due to a parental dam effect, could result in the entire lot of fry being later rejected.
Although it would be advantageous to remove any unacceptable lots of eggs from production as soon as
possible, rejection of large egg lots even in a normal hatchery situation is costly, and with the added effort
of including the transgenic component in the development, it could be prohibitive. In any event, it would
appear that further work is required to resolve the best sampling and screening methods once some
guidelines develop concerning acceptable limits of sterility.

Because a single large commercial hatchery can produce in excess of one million smolts per year,
what confidence level should be prescribed for such a hatchery in order to reduce risks to an acceptable
level prior to authorization for the stocking of smolts in sea pens? If we look at other regulations that
depend on detection probabilities, such as the Canadian Fish Health Regulations, which deal in matters of
similar concern being designed to prevent the transfer of infectious diseases to natural population, we find
that the required sampling for certification of a facility to practice in the interprovincial (and often
international) transfer of gametes or fish requires a maximum sample size of 150 fish per lot. This
sampling level is sufficient to detect a pathogen carrying fish at the 95% confidence level if carriers are
prevalent at 2% (Gillespie et al. 1974). Is the risk of negtive impacts from gene transmission any more or
less serious than those resulting from disease transmission and if so how much?

FITNESS CONSIDERATIONS

Confounding the controversial issue related to the fitness of the transgenic fish, successful
application of the above sterility techniques must also take into account the general suitability of the
triploid condition and its impact on commercially important production traits. Few consumer problems are
anticipated with chromosome set manipulated fish in that polyploidy has been used for decades in plant
agriculture, and triploid trout have been on the market in Europe and North America for several years and
do not differ from normal fish in nutritional quality or consumer safety. It would be encouraging to report
that the triploid condition offers no disadvantages to the fish farmer, and this appears to be the situation
with rainbow trout but not with Atlantic salmon.

The Bay D'Espoir salmon growers on the South Coast of Newfoundland have been successfully
rearing all-female triploid rainbow trout in sea pens since 1988 with a production of about 1000 mt of 3 kg
trout in 1996 (Sutterlin and Collier, 1991). Because this species is not endemic to insular Newfoundland,
it was at government insistence that only sterile trout be used to insure that this species would not become
established and compete with native salmonids such as Atlantic salmon and brook trout. Aside from the
delay and start up cost to initiate the lengthy sex-reversing process, triploid trout have proven to offer
several production advantages over normal trout in that they can be reared to a much larger size and the
meat quality and marketing schedule is not compromised by the detrimental effects of sexual maturation.
Such non-reproducing trout have also been shown to offer some promise in trials in Cape Breton, N.S.
(Stewart, 1996) and in the United Kingdom (Johnstone, 1996). A/F Protein has only recently injected trout
eggs with the GH construct at its new hatchery in P.E.I., and it is encouraging to know that the sterilization
technology is now available for this species.

The situation with producing non-reproductive Atlantic salmon does not appear to be as
straightforward despite attempts by government agencies to encourage the industry in Canada, Australia
and Europe to begin producing such environmentally friendly salmon. The problems apparently do not
reside with either the sex-reversal or triploid induction methods (which are nearly identical to those for
rainbow trout), but relate to the general performance and fitness of the triploid condition. Although all-female, triploid Atlantic salmon seem to perform well under optimum conditions they often exhibit a
number of undesirable production traits in the commercial situation not observed in their diploid
counterparts (Benfey, 1991). These include: reduced survival during egg incubation and during marine
grow-out (McGeachy et al, 1996), diminished tolerance of chronic stress (Benfey, 1996), increased
incidences of lower jaw abnormalities (Sutterlin et al, 1987; Jungalwalla, 1991; Hughes, 1992; King and
Lee, 1993; and Lee and King, 1994 ), greater susceptibility to cataract formation (Wall and Richards,
1992) as well as a number of hematological abnormalities (Benfey, 1997). It remains to be seen if these
deficiencies can be resolved through improved nutrition, husbandry or by selecting different genetic stocks.
In certain countries with more moderate winter temperatures, a steriodogenic burst in growth during the
early stages of sexual maturity are being capitalized upon and this advantage would be lost if fish were
sterile. At this time, the prospects of easily getting the transgenes into suitably performing sterile Atlantic
salmon are not altogether clear and perhaps methods other than triploidy should also be explored (Devlin
and Donaldson, 1992).

Different constructs of the same or different genes can be expected to have a range of phenotypic
effects of varying environmental consequence ranging from that of a relatively benign effect of a non-expressed marker gene (perhaps of use in population studies) to genes that alter reproductive success.
These factors, particularly the last relating to transgene fitness in an open system, are going to be
exceptionally difficult if not impossible to predict reliably, and the possible requirement for lengthy and
costly monitoring programs over a considerable migratory range could well exceed the capacity of
government or industry, thereby possibly precluding the use of transgenic fish in such extensive culture
systems. Theoretical treatments using techniques in population genetics to predict rates of genetic
introgression similar to that by Hutchings (1991) and Muir et al. (1996) could provide some valuable
insight, however a component of relative fitness is required for such an analysis. In the case of a salmon
containing a GH transgene, it would be extremely useful to know something about the physiological
energetics of these fish including some estimate of metabolic rates, gross and net food conversion
efficiencies, maintenance ration levels and the influence of temperature on these parameters. It is the
intention of A/F Protein to undertake such studies which are also extremely important from the commercial
perspective. It might develop that the energetic costs of foraging to satisfy appetite and growth potential
cannot readily be met resulting in a neutral or negative competitive advantage. For example, Dunham et
al.(1995) found that GH transgenic catfish, which exhibit a rather modest (33 %) increase in growth rates
in aquarium studies, showed no growth advantage over normal fish when reared in ponds on natural foods
without supplemental feeding, and that the enhanced growth rates of transgenic fish are predominately
confined (as with salmon) to the juvenile stages and as such do not contribute inordinately to reproductive
success. These authors, in their review of the literature, conclude that it is exceptionally difficult to create
a new genotype in established natural populations through the infusion of domestic or even wild genes.

There may be a limit to usefulness of such population and genetics models in that the track record
in Fisheries Resource Management in Canada in recent years, despite efforts by some very capable
fisheries scientists, has resulted in a considerable loss of public confidence in the ability to manage such
complex systems; to expect fish biotechnologist to make predictions likely to be more reliable maybe
asking a lot!

SOME FISH TALES

The general welfare of Atlantic salmon, often referred to as the "King of the Sportfish," is of
considerable concern to a variety of user and special interest groups which include sport/recreational
fishermen, commercial fisherman, conservation associations, indigenous peoples, fish farmers and the
occasional gourmet chef. As a means of revealing the variety of perceived impacts (both negative and
positive), the following hypothetical case history studies ("transgenic scenarios") are provided as contrived
examples of two extreme levels of impact as might be anticipated by groups having different perspectives.

Let us assume that a cooperative of salmonid farmers from a small coastal community in
Newfoundland that own their own hatchery and sea pens wish to put a sizeable component of their
production into transgenic trout fish in order to accelerate growth rates and become more competitive.
Because of the excellent performance in the past, they plan to continue using use all-female, sterile triploid
trout in a location that does not have native rainbow trout, and they feel confident that there will be little or
no negative impact on local Atlantic salmon or brook trout populations. The hatchery manager decides to
import GH transgenic fry from a certified (disease and transgenic) source after they had been screened to
insure that they are 100% all-female and at least 99% triploid. After six months of fresh water culture in
the hatchery, one million smolts are stocked into estuarine pens located thorough the Bay. Two years
later, the trials are deemed a success as improved growth rates are observed at low winter temperatures in
both fresh and salt water, less energy is required for heating water at the hatchery and the production time
and production cost is improved considerably. Although there are the usual number of fish escaping, no
negative impact is observed by threse reproductively incapable trout on salmonid populations in local
rivers. Because of their greater food and energy requirements, it is discovered that the trout do not survive
well outside of the protective aquaculture environment and as an added benefit, a very lucrative estuarine
summer and winter ice sport fishery develops to exploit these trophy size trout that have escaped which
employs many local people including aboriginal groups that serve as fishing guides. The industry expands
providing employment for many of the fisherman displaced as a result of the failure of the traditional cod
fishery. It would appear that Canadian biotechnology has given these farmers an edge whereby they can
better compete with Chilean trout farmers who are blessed with warmer temperatures, better growth rates
and less expensive feed.

In the second scenario, things seem to go wrong at the onset. Ice damage is exceptionally bad the
first winter and combined with several seal attacks, 5% of the total stock ( 50,000 fish) inadvertently
escaping from the net enclosures. This happens close to harvesting time and the fish are averaging 3 kg in
weight. All escaping fish survive and all migrate to the nearest salmon river which has environmental
temperatures and spawning habitat behaviourally conducive to mating by entire group of trout. Of the
50,000 fish, only 500 (1%) are non-sterile diploid fish and produce eggs, but there is a paucity of male
trout around since rainbow trout are not endemic in this area and hybridization with native species is not
possible. Nevertheless, a few stray male rainbow trout from farming activities in Cape Breton (400 km
distant) or from established populations on the Avalon Peninsula manage to find their way to this river and
1.5 million eggs (50%) are successfully fertilized and deposited. Incubation temperatures are ideal and
10% of the eggs hatch successfully and the resulting fry emerge from the gravel at an opportune time, to
encounter excellent food resources resulting in 10% survival to the smolt stage. This results in 15,000
transgenic trout smolts going to sea each containing 50% of the transgenes possessed by their female
parent. After two to three years, 1500 surviving transgenic trout, consisting of both males and females,
return to the same river and undertake spawning among themselves and with other transgenic trout that
have more recently escaped. Because their spawning time overlaps with that of Atlantic salmon and brook
trout, the rainbows compete for spawning habitat and also dig up eggs previously deposited by the two
native species. Their absolute fecundity is also great because of their trangenically enhance oceanic growth
rates, and many eggs are deposited by each female. The juvenile transgenic trout are always hungry and
exceptionally aggressive, displacing salmon from the most productive feeding habitat. Many of the large
transgenic trout overwinter in the estuary and wait at the mouth of the rivers in the Spring for a free meal
of vulnerable salmon smolts migrating to sea. The trout eventually become self-sustaining and spread to
many other rivers. After several years of this abuse, the native salmon and brook trout populations begin
to decline. Sport fishing revenues cease and the aboriginal food fishery fails. Fisheries officers are
instructed to confiscate and destroy all remaining transgenic fish, and the fish farmers suffer severe
economic hardship. There is a profusion of accusations, allegations and litigations accompanied by some
bad press and a large migration of lawyers to this Newfoundland outport community. The remaining free-ranging transgenic trout become so large and aggressive that the Canadian Coast Guard has to issue a
warning to bathers and small boat operators, and an element of public safety is added to the debate.

The above "Jurassic Jaws" scenario is put forthnot as an attempt to be humorous, facetious or to
trivialize the seriousness of such issues, but to challenge the government, scientific community and the
public to sort out which elements are likely to be possible, which are probable and which might be best
considered pretentious or fictitious. While the first scenario might be considered especially optimistic in
that no technical or environmental problems arose during this field trial, many of the predictions made in
the second scenario ignore many biological facts, are alarmist and extremely unlikely.

The required analysis to use transgenic Atlantic salmon in the farming industry in British Columbia
(which as with trout above would be also be a non indigenous species) would likely involve assessing
elements of risk similar to that above with a determination being made as to the acceptability of using
mono-sex fish over truly sterile fish. In eastern Europe, the State on Maine, USA and in Eastern Canada
where Atlantic salmon are endemic, the added impact component of genetic introgression of the transgene
within the species would have to be included in the risk analysis and the frequency of non sterile
transgenic fish could become the central issue. A proposal to rear transgenic trout or Arctic char in a
ground water hatchery in central Canada would involve somewhat different considerations. It is therefore,
apparent that such exercises will have to be quite gene, species and site specific, and simple generalizations
concerning the risks (or benefits) of transgenic fish are not likely to be particularly useful.

Although perhaps a far-fetched justification for the commercial use of transgenic fish, the follow
question may be legitimate. If the previously documented neutral or negative effect that the sterile triploid
or monosex condition seems to have on commercial Atlantic salmon operations could be offset by a positive
transgenic component, would the industry not be more inclined to use sterile fish? And if such were the
case, would the risks (real or perceived) to wild stocks be any greater than that projected or perceived
under current practices?

ACKNOWLEDGEMENTS

The authors of this paper would like to thank the Canadian funding agencies (The National
Sciences and Engineering Research Council, and the National Research Council of Canada) for the many
years of support for this research. We particularly acknowledge the assistance of our colleagues at St.
Andrews, N.B., Dick Saunders (DFO) and Greg Goeff (HMSC), who have contributed much to this
project. Comments on the manuscript by Dr. Dick Alderson were most helpful.

Chourrout, D (1984) Pressure-induced retention of the second polar body and suppression of the first
cleavage in rainbow trout: production of all-triploids, all-tetraploids, and heterozygous and
homozygous diploid gynogenetics. Aquaculture 36: 111-126.